Semiconductor integrated circuit

Abstract

The present invention provides a semiconductor integrated circuit which can reduce power consumption without hampering operation of a CPU. A power supply control circuit 40 installed separately from a CPU 10 detects a signal (e.g., an idle signal Si) from the CPU 10 installed on a semiconductor chip 1. In response to the idle signal Si, the power supply control circuit 40 controls supply of a source voltage Vp to the CPU 10 by controlling a switch element 30—1. This makes it possible to control power supply efficiently without hampering the operation of the CPU 10.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a semiconductor integrated circuit and, more particularly, to a semiconductor integrated circuit which reduces power consumption of functional blocks.[0003]2. Description of the Related Art[0004]A technique related to power supply control is described in Japanese Patent Laid-Open No. 2004-192296.[0005]A power consumption control circuit described in Japanese Patent Laid-Open No. 2004-192296 generally controls power supply to a functional macro—stops power supply or changes supply voltage—according to the internal state of the functional macro. Specifically, the power consumption control circuit receives, from the functional macro, a signal which represents the internal state of the functional macro. When the signal indicates an idle state, the power consumption control circuit stops power supply to the functional macro. When the signal indicates a memory access state or the like, the pow...

AI Technical Summary

Benefits of technology

[0010]That is, according to the present invention, since the power supply control circuit installed separately from the central processing unit controls the first switch in response to the first signal output by the CPU and the first switch controls source voltage supply to the functional macro, the central processing unit does not need to control the state of the functional macro unlike the conventional techniques. Consequently, the central processing unit can perform primary processes without receiving periodic interrupt signals for power supply control. Thus, the present invention can efficiently control power supply without hindering operation of the central processing unit.

[0011]The present invention can efficiently control power supply to functional macros in a semiconductor integrated circuit.

Problems solved by technology

Under such conditions, more time is required to complete the primary processes of the CPU, resulting in increased power consumption.

Consequently, the technique described in Japanese Patent Laid-Open No. 2004-192296 has a technical problem to be solved: namely, the semiconductor integrated circuit cannot control power supply efficiently.

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